The poster said, "The shift quality is okay, smooth, that is, but does seem to be a bit late at moderate throttle positions." If the bowden cable was that far off, the other shifts would not be just "a bit" late. I am assuming his description is accurate, since that's all we have to go on. The 300E had 1st-gear start beginning in 1991.

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2012 E350
2006 Callaway SC560

This is an image of the bowden pressure cable arrangement on a 1991 300CE. Probably typical for any 300 during that time. Picture taken with the air cleaner removed. Bowden cable is attached to the throttle linkage and is directly behind the throttle body.

Using a 13mm wrench, turn the plastic yellow adjustment nut counter-clockwise when facing the vehicle to shift sooner, clockwise to shift later. The arrow and mark were not necessarily aligned when I had it where I wanted it. Be sure to inspect the vacuum line to the vacuum modulator for a tight fit while you're at it, but don't tug too hard or you will pull it loose from the transmission end and you will have to crawl under the car to reattach it.

I've seen a lot about the vacuum but the cable is part of the equation, too.

Please note: This car is new to me and I still tinkering with it and learning it, but I thought that this might be a start to show you what at least one bowden cable arrangement might look like.

I adjusted the Bowden pressure cable and took a pic while I was at it. The shift points have dropped, and it seems to operate fairly well. Shifts at normal operating temp 2nd to 3rd are about 2,200-2,500 for moderate throttle positions and normal driving situations. The shift quality is a bit firm, especially 3rd to 4th. I'd like it to be a little softer so would a 1/4 turn counter-clockwise adjust of the vacuum modulator help? (Counter-clockwise for softer shifts, Clockwise for firmer shifts, right?) Or should I just leave it alone. Vacuum line is tight and should not be leaking. Do softer shifts cause more wear on the tranny?

Also, since I adjusted the bowden cable, it takes a lot of throttle to get it to downshift, say, to get up a hill in the 40-50 MPH, 2,500 RPM range. I don't want to have to floor it to get it to downshift everytime I need a little more power.

Is there a way to get the tranny to use it's 1st gear? It is a bit sluggish off the start.

Thanks for all the information. I'm new to Mercedes-Benz so I'm still learning.